Correct and Effective Mask Use

The Optimistic Scientist explains...Corrective and Effective Mask Use

A mask may not protect the wearer, but it will help prevent the wearer from spreading the virus to other people.

Masks prevent respiratory droplets (produced by talking, coughing, and sneezing, for example) from spreading germs to other people. Some people find typical masks uncomfortable because they can trap moisture against the face and may opt for ones with one-way valves or vents. Unfortunately, this creates an effective channel for exhaled droplets to reach others, defeating the purpose of the masks. This is why the CDC recommends using masks without an exhalation valve or vent.

Masks alone are not enough.

You can reduce the spread of SARS-CoV-2 by wearing masks in addition to practicing other preventive measures, such as social distancing, frequent and effective handwashing, and cleaning and disinfecting frequently touched surfaces.

Surgical masks are ONE-WAY.

Let me repeat that one more time for emphasis. Surgical masks are ONE-WAY. The concept of flipping the mask based on situation is a MYTH. If you wear the mask inside out, it’s not going to help anyone.

The Optimistic Scientist shows how to properly wear a surgical/procedure/face mask. The blue side should face outwards.
If the mask has a blue or green side, this is the side that should face other people.
If the mask is all white, put the softest side to your face.
The Optimistic Scientist shows how to properly wear a surgical/procedure/face mask. The blue side should face outwards and the bendy part should be on the top and pinched around the bridge of the nose.
Surgical masks don’t work unless they completely cover your nose and mouth.
Pinch around the bridge of your nose.

Why are they one-way? Surgical masks can’t be reversed because they have three specialized layers. In the name of science, I dissected one so I could show you.

Zoomed in view of a surgical mask illustrating the stitching that links three distinct layers.

Zoomed in view of the stitching that keeps the 3 layers of a surgical mask together.

Zoomed in side view of a dissected surgical mask, illustrating the three distinct layers.

Dissected surgical mask, side view.

These handy little forms of PPE (personal protective equipment) are specifically designed to protect a patient on the operating table from the respiratory droplets of a surgeon, who is breathing, talking, and potentially sneezing above a patient’s open abdomen/brain/etc. They do this by intercepting and diffusing those droplets and by minimizing lateral dispersion (sideways spread). First, droplets are captured by a water-loving absorbent layer, typically white. Anything that makes it beyond this layer is then filtered out (remember, these filters won’t trap viruses because they are really tiny). If a droplet isn’t caught by the filter, it hits the final, water-repellant exterior layer, often blue or green, which further helps to minimize the chance it will spread to those around the wearer. These masks are not intended to protect the wearer.

Mask Layers

Outside – water repellent

Middle – Filter

Inside – water absorbent

Zoomed in view of the different materials used in the three distinct layers of a surgical mask labelled with the orientation.
Zoomed in view of the inside layer of a surgical mask. This is the moisture absorbent side and should be worn closest to your face.
Zoomed in view of the middle layer, or filter, of a surgical mask. Regardless of orientation, this remains in the middle. If the mask is worn incorrectly, the efficiency of this filter can be severely compromised.

Zoomed in view of the outside layer of a surgical mask. This is the moisture repellant layer and should be worn facing the wearer's environment. If worn incorrectly, this layer touches the face and allows the mask to get wet. This becomes uncomfortable but also severely reduces the efficiency of the mask at filtering droplets and protecting others. It's also uncomfortable for the wearer.

What happens if my mask is inside out?

If your mask is inside out, the moisture repellant side is up against your face. When you exhale, water vapor won’t be absorbed by the mask and it will become wet. The mask then loses its ability to efficiently filter and trap droplets and you will likely find the damp mask pretty uncomfortable. With the mask inside out, the absorbent layer now faces the environment and has become a droplet landing zone. If you touch the contaminated exterior of the mask and then touch your face, or re-use the mask instead of replacing it, you increase your chances of getting sick. This virus is already super effective at spreading; let’s not make it even easier!

Masks don’t work when:

  • dirty or wet
  • upside down/inside out
  • torn
  • not covering your nose or your mouth completely

Under any of the above conditions, the filtration efficiency and protective capability of the mask is compromised.

Mask illustrating an easy way to remember which side should face out. Brr it's cold outside. B for brr and blue, means the blue side is on the outside.
I’m a sucker for fun ways to remember things, so here you go!
B is for blue and brrrr.

Didn’t the CDC say NOT to wear masks?

Yes, but here’s why. Previously, the CDC and the WHO recommended that only those with symptoms should wear masks. They’ve since modified this recommendation because:

  • SARS-CoV-2 can be spread by asymptomatic individuals or before symptoms appear
  • Surgical masks are prioritized for healthcare workers coming into contact with many patients

You should still prioritize surgical masks for healthcare workers. Cloth masks, however, are more effective than not wearing anything — although not a substitute for social distancing, not touching your face (cloth masks also provide a tactile reminder not to touch your face), and frequent hand washing.

Let’s Review!

  • Wear a mask that properly fits, and in the right orientation.
  • Don’t wear masks with exhalation valves/vents.
  • Always practice social distancing and hand hygiene. Wearing a mask is not a substitute for these behaviors.
  • Don’t touch your face!

A final note

I don’t need to tell you that this pandemic has been difficult for so many people. Everything about our daily lives and how we provide for ourselves and our families has been affected. The disproportionate effect of COVID-19 on certain racial and ethnic minority groups has led to increased awareness of systemic racism and inequity, from housing to education and everything in between. If you don’t consider this virus a serious problem, I urge you to thoughtfully reflect on what privileges you may knowingly or unknowingly hold, and how no individual experience is reflective of our country as a whole. If you’re in a position to doubt whether or not this is a big deal, you may not recognize how fortunate you are to have some degree of financial stability or greater access to health care that others do not. I urge you to trust evidence-based science and to trust your public health officials. Please protect yourselves and others by observing the rules of masks, distance and hygiene.

Do you have questions, comments, or suggestions for my next experiment/dissection?

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All About Testing

There are 3 kinds of tests for SARS-CoV-2 under the FDA’s Emergency Use Authorization (EUA): Molecular, Antibody, and Antigen testing.

Molecular test — RT-PCR (Reverse transcription polymerase chain reaction): This is a molecular in vitro diagnostic test that identifies the presence of virus in the body through collection of nasopharyngeal, oropharyngeal, or other respiratory specimens by swabbing.

A false-negative result may occur if:

    • a specimen is improperly collected, transported or handled
    • inhibitors are present in the specimen
    • there are too few virus particles present in the specimen.

Detecting the presence of the virus doesn’t indicate whether or not someone is infectious.

A single negative result does not mean you can skip social distancing or stop wearing a mask.

A negative test result only means that you didn’t have COVID-19 at the time of testing. It’s possible your sample was collected too early in your infection.

You could also be exposed to COVID-19 after the test and then get infected and spread the virus to others.

If you develop symptoms later, you may need another test to determine if you are infected with the virus that causes COVID-19.

Antibody Test — Serology: Blood test with a turn-around time of typically same day, but sometimes can take a couple days. Serology is especially important because it may detect previous infections in people who had few or no symptoms.

Antibodies are proteins made by the immune system in response to a foreign substance (called an antigen). Each antibody recognizes a small portion of a single antigen (antibody specificity) so an antibody that recognizes the virus that causes chickenpox will not recognize the virus that causes measles.

There are 5 different types, or classes, of antibody: IgG, IgM, IgA, IgE, and IgD. Most rapid novel coronavirus tests look for IgG and IgM. After an infection, your body starts to produce IgM antibodies first, which can be detected after about a week and hang around for a couple weeks after your symptoms start. IgG antibodies are part of your immune system’s long-term arsenal, detected after 2 weeks from the start of symptoms, peaking around 30 days, and hang out for months or even years after you recover.

IgM antibodies: Produced first, detected ~ 1 week after start of symptoms. Because it is only detectable for a couple weeks, it is used to determine recent infection.

IgG antibodies: Produced later, detected ~ 2 weeks after start of symptoms. Because it can be detected for months or years after infection recovery , it is used to determine past infection.


In general, there are two kinds of antibody test methods: binding antibody or neutralizing antibody tests.

Binding antibody tests: These tests use purified proteins of SARS-CoV-2, not live virus, and can be performed in lower biosafety level laboratories (e.g., BSL-2).

Point-of-care (POC) tests usually use lateral flow to detect IgG, IgG and IgM, or total antibody in whole blood, serum, plasma, and/or saliva. A common example of a lateral flow device is a home pregnancy test. Some point-of-care tests can be performed on blood collected from a fingerstick rather than a blood draw.

Laboratory tests typically use ELISA (enzyme-linked immunosorbent assay) or CIA (chemiluminescent immunoassay) to detect IgG, IgM, and IgA antibodies, either individually or as total antibody.

Neutralizing antibody tests: As of July 2020, the FDA has not authorized the use of neutralization tests for SARS-CoV-2 yet.  In this test, a serum or plasma sample is infected with live virus in a test tube to determine if the antibodies are functionally capable of preventing infection.  Because this method involves the live virus, it requires a higher biosafety level (BSL-3 or BSL-2 laboratory).

Virus neutralization tests (VNT): Here, the SARS-CoV-2 virus comes from a clinical isolate or is modified for the assay. This testing must be done in a BSL-3 laboratory and can take up to 5 days.

Pseudovirus neutralization tests (pVNT): This test uses a non-SARS-CoV-2 modified virus (e.g. vesicular stomatitis virus, VSV) that has a piece of protein from SARS-CoV-2 attached to it. This testing can be performed in a BSL-2 laboratory, depending on the particular strain.

Unfortunately, just because we can detect them doesn’t automatically mean that they can provide immunity/protection from reinfection.

Antibody testing results shouldn’t be used to decide if someone can return to work. It also shouldn’t be used to group people together in settings such as schools, dormitories, and correctional facilities that increase the risk of transmission.

Antigen test — Rapid: Rapid diagnostic test with a turn-around time of less than one hour. Antigen tests look for specific proteins on the surface of the virus and can diagnose an active infection.

Unlike antibody tests that detect your immune system’s response to the virus, antigen tests detect viral proteins directly. The two major antigenic targets of of the SARS-CoV-2 virus are the spike glycoprotein (S) and the nucleocapsid phosphoprotein (N).

Depending on the complexity of the method, these tests can be performed in <30 minutes or may take a couple of hours. 

Have general questions? Comments?

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Resources/Further Reading

Interim Guidelines for COVID-19 Antibody Testing (CDC, updated 8/1/2020)

Great Video Explanation of Antibodies & Serology Tests (Beckman Coulter, 5/22/2020)

Washington State Stay Home, Stay Safe 2 Week Order

Please be sure to refer to the original documents for questions or concerns relating to a specific situation.

“The less time we spend in public, the more lives we will save.”

Governor Jay Inslee


  • How Long? 3/25/20 – 4/5/20
    • Unless extended
  • You can still safely go outside as long as you remain at least six feet from each other.
  • Essential businesses can remain open if they follow specific sanitation and social distancing policies outlined by the CDC and WA public health.
  • Gatherings are banned
    • regardless of the number of people, public and private

What Does This Mean For Individuals?

You can only leave your home to do one of two things:

  • Essential activities 
    • Obtaining necessary supplies and services 
      • for family or household members and pets
      • such as groceries, food and supplies for household consumption and use
      • supplies and equipment needed to work from home
      • products necessary to maintain safety, sanitation and essential maintenance of the home or residence
    • Engaging in activities essential for the health and safety
      • of family, household members and pets
      • seeking medical or behavioral health or emergency services
      • obtaining medical supplies or medication
    • Caring for someone else
      • a family member, friend, or pet in another household or residence
      • to transport a family member, friend or their pet for essential health and safety activities
      • to obtain necessary supplies and services
    • Engaging in outdoor exercise activities
      • walking, hiking, running or biking
      • ONLY IF appropriate SOCIAL DISTANCING practices are used
  • Employment in essential business services 
    • Healthcare / Public Health sector
    • Emergency Services sector (Law Enforcement, Public Safety and First Responders, Public Works)
    • Food & Agriculture
    • Energy (Electricity, Petroleum, Natural and Propane Gas)
    • Water & Wastewater
    • Transportation & Logistics
    • Communications & Information Technology
    • Critical Manufacturing
    • Hazardous Materials
    • Financial Services
    • For more details, see the Essential Critical Infrastructure Workers list
  • Doesn’t Apply If:
    • If your home/residence becomes unsafe, you are permitted/urged to leave and stay at a safe alternate location (e.g. victims of domestic violence).
  • Doesn’t Apply If:
    • If you are an individual experiencing homelessness, but you are urged to obtain shelter, and governmental and other entities are strongly encouraged to do as much as they can to increase their capacity to help as many people as possible.

What Does This Mean for Gatherings?

Effective midnight on March 25, 2020 until midnight April 6, 2020 (unless extended beyond that date)

  • No public and private gatherings
  • Regardless of the number of people involved
  • doesn’t apply to people who are part of a single household or residential living unit.

What Does This Mean for Businesses?

All non-essential businesses in shall cease operations by midnight March 25, 2020 except for performing basic minimum operations.

All essential businesses are prohibited from operating unless they establish and implement social distancing and sanitation measures established by the United States Department of Labor’s Guidance on Preparing Workplaces for COVID-19 and the Washington State Department of Health Workplace and Employer Resources & Recommendations.

List of Links

Resources: SARS-CoV-2 and COVID-19

What to do if you have symptoms of coronavirus disease 2019 (COVID-19) and have not been around anyone who has been diagnosed with COVID-19

What to do if you have confirmed or suspected coronavirus disease (COVID-19)

National Institutes of Health (NIH) – Vaccine Research Efforts on Coronavirus (COVID-19)

Schools/Education – For updates on school closures and information and guidance for parents

Employment Security Department of WA State – Links and FAQs for workers and businesses affected by coronavirus

Business and Workers – Links and FAQs for workers and businesses affected by coronavirus

Retail businesses guidelines from Department of Public Health

Workplace Practices – handwashing and social distancing recommendations for employers

Have general questions? Comments?

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Reliable Sources of Information

Where can I find the most reliable, up-to-date numbers on confirmed cases?

There are several resources out there that compile the information from multiple sources. When evaluating any information, please remember to critically assess:

  1. The source itself and their goals
  2. How the data and findings are described
  3. What has been reported, and what has not; and
  4. The quality of the information

Globally –> World Health Organization (WHO)

Globally –> Abdul Latif Jameel Institute for Disease and Emergency Analytics/Imperial College (J-IDEA):

United States –> 

  1. – Combined White House/Dept of Health & Human Services/CDC resource, this is your starting point for information & resources at the federal
  2. Centers for Disease Control (CDC)

NOTE: The CDC is providing accurate numbers for the country as a whole, but if you want more up-to-date information on a daily basis, please check the department of health or public health websites for your particular state or county. If you click the CDC link above, and then click a state, it will bring you to that department of health’s website.

Washington State –> Washington State Department of Health

NOTE: The state of Washington’s department of health website also has data broken down by county.

King County –> Public Health – Seattle & King County

Why do some numbers vary between sources (NY Times, Politico,, etc)?

It depends on two main things – when you’re looking, what you’re looking at, and where the numbers are coming from. Some sources update only once a day, others multiple times a day. Some pull from multiple inputs, or count confirmed cases in addition to information gained from reporting and interviews with credible sources. Some may have more than one laboratory in a given area that may be reporting with different frequencies during a given day. Your best best is to stick with the public health authority at the level your question is directed to, but consulting multiple sources like the ones listed above can give you the big picture view of this pandemic.

John’s Hopkins has a live tracker that provides interesting insights.

Have general questions? Comments?

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The Novel Coronavirus – Key Terms

This image has an empty alt attribute; its file name is sars-cov-2-1.jpg
The novel coronavirus, or SARS-CoV-2, is the virus responsible for the COVID-19 illness.

What is the novel coronavirus?

Okay, first things first, let’s start with a few key terms to clarify any mixed messages you may be receiving.

Coronavirus: The name given to a family of viruses that cause disease of varying severity in mammals and birds. Viruses from this family can be responsible for the common cold, but other members of this family have caused two large-scale pandemics in the past two decades, sudden acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). Viruses are classified into families based on their structure and genetics, so it’s kind of like coronaviruses are the Mariners.

SARS-CoV-2 (sudden acute respiratory syndrome coronavirus-2 or the novel coronavirus): This is the specific name of the novel viral organism. If we continue our example from above, this would be a specific baseball player (Ichiro, Ken Griffey Jr, etc). It’s novel, or new, because this a virus that our immune systems have never seen before.

COVID-19: This is short for coronavirus disease 2019 and the name of the disease/illness caused by the novel coronavirus that originated in Wuhan, China in 2019.

Epidemic: A sudden increase in the number of cases of a disease above what is typically expected in a given area.

Pandemic: An epidemic that has widespread human infection in multiple countries across the globe.

Signs: Objective measurement to characterize an illness during a physical exam by a healthcare provider (e.g. temperature, respiratory rate, oxygen saturation).

Symptoms: Subjective evidence of an illness or abnormal process occurring in the body and reported by the patient (e.g. fatigue, nausea, anosmia, ageusia, myalgia).

Incubation Period: The time from when someone is infected to when symptoms develop. Based on existing evidence-based research, the incubation period of SARS-CoV-2 and other coronaviruses (e.g. MERS-CoV, SARS-CoV) ranges from 2–14 days. 50% of people will become ill 5 days after infection.

Infectious Period: The time when an infected person, who may not be showing symptoms, can transmit the virus to others. While it varies from person to person, it is typically ~ 7 days.

Molecular test — RT-PCR (Reverse transcription polymerase chain reaction): This is a molecular diagnostic test that identifies the presence of virus in the body through collection of nasopharyngeal, oropharyngeal, or other respiratory specimens by swabbing. The turn-around time for results varies greatly depending on the laboratory doing the test, but the current range is somewhere between 1 and 5 days.

Antibody Test — Serology: Blood test with a turn-around time of typically same day, but sometimes can take a couple of days. Serology is especially important because it may detect previous infections in people who had few or no symptoms.

Antigen test — Rapid: Rapid diagnostic test with a turn-around time of less than one hour. Antigen tests look for specific proteins on the surface of the virus and can diagnose an active infection.

Have general questions? Comments?

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